Approximately one in six couples find themselves involuntarily infertile. This translates to between two and four million couples in the United States alone. Although numerous tests are available for diagnosing infertility problems, 16% of all couples that seek medical treatment are diagnosed with what is described clinically as “unexplained infertility”.
Tests to evaluate fertility in men have relied on conventional sperm analysis, in which sperm count and sperm motility are the primary factors. However, in conventional sperm analysis there are no strict threshold levels separating fertility from infertility, except in the situation wherein there are no moving sperm, which is always associated with infertility. A sperm count of twenty million sperm per milliliter or greater is generally considered to be in the fertile range, whereas a lower count is considered subfertile. There is some disagreement on this in that some laboratories and clinicians use rates of thirty million sperm per milliliter or forty million sperm per milliliter as the fertility threshold. These values are not fixed in that it has been determined that twenty percent of human males with counts below twenty million sperm per milliliter will father children and as many as fifteen percent of human males with normal sperm counts may have some degree of sperm dysfunction due to other reasons which interfere with fertility. A sperm specimen with normal sperm count or with normal sperm motility does not invariably establish fertility in that individual. In addition, there is disagreement as to what constitutes the lower limit of sperm motility that can be considered normal or fertile, with estimates ranging between forty to sixty percent of the sperm in a given sample. In summary, conventional sperm analysis is not one hundred percent accurate, and is not a reliable indicator of male fertility. Thus, there remains a need for diagnostic tests for determining fertility in males that are both accurate and easy to use.